556 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 
upper spring, the reduction and maintenance of the temperature of the 
water to that degree of coldness necessary to delay the hatching until 
early spring is a work not easily accomplished, evidenced by the results 
of the season just closed. If it is considered immaterial whether white- 
fish are hatched and planted in February or in April, then a more suit- 
able locality would be difficult to find; for with an adequate quantity of 
ova to consume the entire yield of the supplying spring the water would, 
even against the adverse influences of the ice-water pond as now used, be 
still warm enough to bring forth the fry as early as February, thereby 
shortening the season by two or three months, with its attendant ex- 
penses. 
PREPARATORY WORK. 
During the month of August, 1880, instructions were received from 
United States Fish Commissioner Prof. Spencer F. Baird for the pros- 
ecution of the work of propagating whitefish at the Northville station 
for the season of 188081. As provisions were made for conducting op- 
erations quite extensively, preparations commensurate with the contem- 
plated extent of the work were essential. Preliminary work, then, was 
immediately begun, and consisted for the: most part of the following; 
Cleaning and enlarging the spring pond ; devising and introducing some 
plan of drawing the surplus water immediately from its source at the 
head of the pond, instead of from the foot, as had previously been done ; 
enlarging ice-water pond; providing increased facilities in the way of 
conducting pipes and trunks for conveying the water from the spring 
pond to the ice-water pond, and from thence to the tank room ; repairs 
to the hatchery and a thorough overhauling of the appliances of the 
hatching and tank-rooms; providing increased facilities for carrying 
spawn; and, finally, the construction and arranging of feeding troughs 
and equipping the same with the Chase hatching jars. 
The object, of course, of drawing all the waste water from that por- 
tion of the pond fed directly by the spring or springs was to obtain the 
minimum quantity of spring water to be cooled, allowing only enough 
of the latter to mingle with the pond to maintain it against the counter 
draught of the ice-water pond for consumption in the hatchery. The 
plan originally intended to secure these results contemplated a division 
of the spring pond into two sections by the erection of a wall or dam, 
thus separating the spring area from the remainder. With the springs 
thus cut off and confined within the smallest possible space, provisions 
for drawing from them the actual quantity needed and also for the dis- 
position of the surplusage could be easily made. But a careful inspec- 
tion of the premises and a complete investigation of the character of the 
bottom of the pond disclosed the fact that this plan could not be carried 
out Save at an expense greatly in excess of the estimates, and it was, 
therefore, abandoned and substituted by a simple arrangement, the 
